The Dallas daily herald. [volume] (Dallas, Tex.) 1873-1887, 1887-04-08
HOW TO MAKE GLASS.
The Process or Manufacture OF tho Different
Kinds.

4. 1aUlOru uc1ucrSolli ptoncSoOi VI
chemNtry and physics in the Indus
trial Training School, lectured ut
Franklin Institute recently on "Glass
Making" After briefly retailing the
history OF the art ofmaking glass, and
what glass was, Mr.. Henderson said;
1.-THE operation OF glass making re-
quires both skill and patience; nicely
in the mixture OF the materials and
delicacy and dexterlty in the manu-
facture OF the finished product. There
is no industry so benefited by tho
discovery Unnatural gas as this. Euro
pean manufacturers havelongused ar
tifcial gas, it having been found that
smoke and sulphurous fumes from the
coal affected the clearness OF the pro.
duct. Where. in this country, nat
ural gas is not obtainedable. man
ufactured gas is taking the place OF
coal in the principal furnaces. In the
furnace huge pots OF fire-clay, with q
capacity OF |, 400 to 1,600 pounds
OF material, are filled with the
mixed substances called the batch,
composed OF sand, lime and carbon
ate or sulphate OF soda in varying
proportions. Into chamber beneath
them the burnnggas streams. Above
each pot is an opening into the cham
Der in which it stands, through which
the blowppe is dipped into its con-
tents. The blowpipe is a heavy tube
of wrought iron, its lower end some
what Hanged.
In making the windowglass, the OPP
orator repeatedly dips his pipe into
the molten glass, until on its end IS u
mass of fused glass. Whirling this
rapidly and dexterously it assumes II
pear-lika shape. The operator
blows into the pipe, mould
ing the huge bubble as it grows to the
size and shape OF a carboy. The blow
ing now ceases and the operator
swings his bubble in n pit beneath his
platform, until by it's weight it length
ems into a cylinder and coos to hard
ness. The top and bottom OF this
cylinder are ingeniouSlY got rid OIL,
and q cold IRON is run along one side
/ the remaining cylinder, making u
straight crack through its entire length.
| 1t is then put into an oven, crack up
permost, as it is heated it falls out in
| to n flat plate and is "ironed smooth
| by u flat piece OF wood on the end oil
d long bar. Lastly, it is put into the
annealing furnace, heated and allow
ed to cool very gradually, to tougher
the glass. 1t may then be cut up into
panes. Crown glass is made by gath
ering the mass in the end OF the pipe,
blowing a small bubble and transfer
ring it TO an iron bar. The opening
left by the blowpipe is gradually en-
| larged as the mass is whirled until the
mass becomesa circular fiat disk. It's
disadvantages are its variable thick
ness and the smallness OF the panes.
Plate glass is of the same compost
ton as the former, but purer materi-
ais are used. 1t is cast on an iron or
bronze table from n huge ladle swung
from the furnace to the table. Rollers
pass over it to secure uniform thick
ness. The result is a rough slab, only
translucent. 1t is made smooth with
sand and emery, and polished with
burnt sulphate OF iron. .
In making the batch Tor optical
glass lead is used instead OF lime. This
branch of the art reaches its highest
| -, a n
portant lenses for telescopes are made
on this side OF the Atlantic. Another
llat glass is seen in the car windows,
the design being pressed into the heat
ed pane, and the marks subsequently
polished.
Mosaic glass is translucent, colored
unevenly by arsenic, tin and other
compounds, and is coming into use IN
preference to stained glass, its dura-
bility and richness OF shading being
superior to the latter.
It is cast in small pieces, the opera
tor himself not knowing exactly how
the product will look, and the artist
consequently can not have his pieces
made to order. a memorial window
in Milwaukee, made OF this glass, the
subject being Christ Leaving the Hall
of Justice contains 200 figures.
Mr.. sunk then made in miniature,
from class tubes, some OF the articles.
Briefly describing the process he said;
Hollow.ware is either blown or press.
ed. The furnace used in making it is
the Ferrari or tank furnace, the hot
air impingingon aconstantly renewed
heap OF material in reverberatory
chamber, the fused product flowing
away INTO a tank, With openings above
it similar to those in other furnaces. BY